Pumping system for gold dredges



June 15, 1937. w, s TAYLOR ET AL 2,083,582

PUMPING SYSTEM FOR GOLD DREDGES Filed Jan. 20, 1936 V111 S.Tay1o1- MlsonPrice Patented June 115, 1937 PATENT OFF-ICE 7 2,083,582 PUMPING SYSTEMFOR GOLD DREDGES Will s. Taylor and Wilson T. Price, Seattle, Wash.,assignors to U. S. Gold Dredger Corporation, Seattle, Washington Wash.,

a corporation of Application January 20, 1936, Serial No. 59,914

12 Claims.

Our invention relates to pumping systems, and more particularly to avacuum type pumping system for use in a dredge for raising free gold andgold-bearing materials from the. beds of streams and other bodies ofwater. This application is a continuation in part of the application ofWill S. Taylor, Serial No. 38,995, filed September 3, 1935.

It is well known that suction dredges are old and suchdredges have beenused heretofore in gold-recovering operations. Attempts have been madeto use such dredges in recovering gold from stream beds and the likewith little success. The greater portion of the gold, in deposits ofthis kind, usually lies below a stratum of sand, gravel and rock.Embedded in this stratum are stones varying in size from pebbles up torocks six or eight inches in diameter.

Ordinarily a suction pipe of about three inches in diameter is employedwith a pump which can create a suction suificient to raise a rock six oreight inches in diameter. As a result, when such a rock is encountered,or in fact any rock of moderate size which will not pass through thepipe, it is drawn upward to engage more or less tightly over the end ofthe suction pipe. Immediately the flow of water and material up throughthe pipe is completely or largely blocked. With its intake obstructedthe pump will begin to draw air through its outlet and will consequentlylose its prime, whereupon a vacuum will no lon er be created and therock will drop from the end of the pipe. At this point, however, nowater is flowing through the pump, and it must be reprimed and the wholeoperation started over aga n after this event. Moreover, when the pumphas been reprimed it will not flow full or build up to its highestvacuum for some little time. Since rocks are frequently encountered, alarge amount of time is ordinarily lost in repeatedly resumingoperations after they have been interrupted by blocking of the pipe.

It is the principal object of our invention to provide a mechanism whichwill prevent any substantial delay in resuming dredging operations afterthe suction pipe has been clogged by a rock or other foreign material.

With this general object in mind it is a particular object to providemechanism for starting operation of the pump at full capacity after theobstruction has been dislodged from the suction pipe, thereby obviatingthe delay attending the building up of the operating,vacuum and volumeand of the pump after it has been reprimed, if such reprimingdsnecessary.

It is a further object to prevent the necessity of repriming the pump inan operation for dropping a rock which isheld over the end of the pipeby the suction thereof.

Still'a further object of our invention is to provide a mechanism forpositively dislodging an obstruction in or at the end of the suctionpipe.

Another object of our invention is to provide an indicator to warn theoperator instantly that the suction pipe has been obstructed so that hemay take immediate steps to free the pipe.

A still further object of our invention is to provide means forproducing a sustained vacuum affording a continued suction in thesuction pipe, even after it has become b1ocked,'for example by an objectseating over the end of the pipe to cut ofi or at least to decreasesubstantially the flow therethrough.

All these objects are obtained with simple mechanism having few parts.Furthermore, our mechanism is of rugged construction, so that it will bereliable in operation and cannot be injured by passage therethrough ofheavy and jagged pieces of rock, nor can it become easily clogged bypieces of material of a size to pass through the mouth of the suctionpipe.

Other objects, and more particularly those inherent in the preferredconstruction of our device, willbe apparent from a study of the drawingin connection with the following description.

Our invention includes the novel parts, and in particular thearrangement of such parts each with relation to the other, as shown inthe drawing, described in the specification, and defined in the claimsappended to the latter.

The mechanism shown in the drawing is one which we have found operatessatisfactorily to carry out our method, but it is to be understood thatthis device is merely illustrative and the proportion and arrangement ofparts may be varied to some extent without appreciably affecting theeflicient operation of the device.

Figure 1 is a perspective view showing the general arrangement oftypical mechanism.

Figure 2 is a plan view of our device.

Figure 3 is a sectional view of the vacuum tank taken along the line 3-3of Figure 2.

Our system is primarily intended to be mounted on the scow S, sothat itmay be located easily for efficient operation upon gold bearing materiallocated along stream beds or on lake and ocean shores. Our device can beoperated, however, in any place where water, either naturally present orartificially furnished, overlies the gold bearing material. As necessaryelements of our pumping system, we employ a prime mover which may takethe form of an internal combustion engine l, and a vacuum creating pumpof the type which can pass solid masses of fair size, commonly known asa rock pump. Such a pump is indicated by the numeral 20, the customarylong bearing 2| being associated with the pump.

Innumerable pumping systems have employed an'internal combustion engineand a rock pump in combination, but as far as we are aware no one hascombined with these devices a vacuum tank of the type which we employ,or has operated any tank according to our method. A rock pump, or anyother type of pump, with which we are familiar, is inefficient alone tocarry out a continuous dredging operation in material through which arescattered rocks of a size larger than the suction pipe mouth, which maybe drawn thereagainst to block the pipe. Any amount of small gravel maybe pumped with such an arrangement, but the moment the flow isobstructed appreciably the pump starts to lose its prime and the vacuumdiminishes and soon disappears.

In our arrangement a vacuum tank 3 is located between a suction pipe 4,controlled by a valve 4!, and a pump intake 5, controlled by a valve 5|and connected to the pump 20. Any suitable type of suction pipe andnozzle (not shown) may be employed, and it may be supported upon the endof a flexible hose 40. From the discharge side of the pump 20 extends adischarge pipe 6 which may empty into a sluice box arrangement (notshown) where the values may be recovered. The key feature of ourinvention is the provision of a vacuum tank 3, and the method ofoperating the same, the particular construction of which is shown inFigure 3. In general this tank consists of a cylindrical casing whichmay be provided at the lower end with any suitable clean-out fitting 30.In the upper end of the tank is connected 2. filling pipe 1 which iscontrolled by a valve 10 for injecting water into the tank. Alsoprovided in the head of the tank is a pet cook 16, the purpose andoperation of which will be explained later.

The suction pipe 4 enters the side of the tank 3 at a point spaced fromthe top thereof. A discharge pipe 5 is connected to the tank, preferablyon the side opposite the connection of the suction pipe 4, and alsopreferably slightly above the connection of the pipe 4 with the tank.This pipe 5 is connected to the intake of the pump 20. Its other end,after projecting into the tank a slight distance, is provided with apart 50, which extends well downward therein and terminates I near thebottom of the tank.

, diameter.

The proportions of the various parts and their positions are believed tobe important in the maintenance of the most efficient operation of thedevice. As an example of one satisfactory installation we recite thefollowing structure. A pump having a capacity of 325 gallons per minutewas employed, with a vacuum tank 28 /2 inches in For strength the tankwas provided with two convex heads. in the lower one of which waslocated a clean-out connection. In the upper head are connected thefilling pipe I and the pet cock 16. To one side, at a point M inchesfrom the top of such side, is connected the suction pipe 4, while thepump intake pipe. 5 enters the side of the tank preferably opposite thatto which the pipe 4 is connected. and at a distance of 10 or 12 inchesdown from the top of the tank side. The down pipe 50 is located near thetank wall, both to prevent undue strain upon the pipe supporting it andto facilitate a smooth flow through the tank from the pipe- 4 on theopposite side thereof into the lower end of the pipe 50.

Before operation of the system commences, and during the operation ofdislodging an obstruction from the suction pipe, water must ordinarilybe delivered to the tank 3, in carrying out our method which will bedescribed hereafter. For this purpose we provide a water pump II, drivenby the engine I, and having its outlet 12 connected with the valve 10which controls the filling pipe I.

To prime the pump II through the intake pipe 13, an open auxiliary tank8 is employed, which tank may be filled'initially with water by means ofa bucket. After the pump H has been primed, its water supply will beobtained from a branch pipe projecting down through the bottom of thescow from the pump intake pipe 13. Further branches 14 and 15 from pipe12 may be provided to fill the tank 8 and to supply water to sluiceboxes, respectively.

When the pumping operation is to be started the first step is to fillthe tank 3 with water through the filling pipe I by means of the pumpII. This filling operation is preferably performed with the pet cock 16open so that the air may escape from the upper end of the tank. As thefilling operation proceeds, the pipes 50 and 5 will normally also befilled, and water will run down into the pump 20 to prime the same. Whenthe tank has been completely filled this fact will be indicated by Waterbeing ejected from the pet cook 16. At this point the pet cock isclosed, and the valve I0 may also be closed to shut off the inflow ofwater to the tank 3 through the pipe I. The pump 20 will not be starteduntil the tank has been filled completely and the pet cock has beenclosed. If it is started before the valve 10 is closed, water may flowinto the tank both through the suction pipe and the pipe I, and pressureexerted by the water flowing in through the latter pipe will clear anyair pockets in the pipe 5.

With the device operating under these conditions after the valve I0 isclosed, the suction pipe 40 will be kept beneath the surface of thewater, but above the stream bed. Since there is no air in the tank 3 itwill remain full of water. At this point the pet cock I6 is opened, butonly for an instant, to admit a small amount of air to the top of thetank 3. Previous to the admission of this air, as mentioned, the tankwas full of water and hence operated merely as a conduit. Now, however,the pressure of the air admitted acts to break the seal between thewater and the head of the tank, and forces the water surface downwardunder the evacuating action of the pump 20. In the particularinstallation which we have described, suflicient air is admitted so thatthe water level drops to a point about a foot from the top of the tank,or to about the center line of the pipe 5, where it passes throughthewall of the tank 3. The system will now be under normal operatingconditions, the vacuum in the top of the tank 3 being somewhat less thanthat which would be created directly by the pump 20. The suction pipe 40may now be lowered into the stream bed to pick up solid material alongwith the water pumped.

The operation could also be started by filling the tank 3 almost but notquite full of water, leaving a very small air space in the top thereof,prior tocommencement of the pumping operation. It is difficult, however,to stop the filling operation and to close the pet cook 16 at preciselythe proper moment. If too large an air space is left, or if too much airis admitted, then the water must be drawn down so far that the pump cannot create a vacuum in the tank substantially equal to thevacuum-creating capacity of the pump itself before theend of the pipe isuncovered, as will be discussed more fully hereafter. It is essential,therefore, that only a-very small amount of air be admitted for properoperation of the device.

When the requisite amount of air has been ad- Til amass:

tank 3 will, of course, have increased, ,but once mitted, and the waterlevel in the tank has dropped to the proper point for normal operation,

the inlet pipe 4 should be slightly below the water surface, so that asmooth discharge into water is obtained rather than a spray intotheyacuum space, and yet no appreciable back pressure from a head ofwater above the intake pipe connection will be present. j

The outlet pipe 5, we have found, should have its center line about atthe surface of the water in the tank, and yet the down pipe 53 shouldreach almost to the bottom of the tank. A pump does not operate properlyunder forced pressure, and hence the pipe 5 should not connect near thebottom .of the tank so that the pump'would be subjected to the head ofwater within the tank. It is desirable to draw water from thebottom ofthe tank, however, so that large pieces of rock and the heavy material,including the gold values, will pass out through the pipe 5 instead ofsettling to the bottom of the tank 3, and so that the dislodgingoperation may be carried out. Also ciliciency of the system is increasedby locating the pipe'5ll on theside of the tank opposite the pipe 4 togive a smooth flow through the tank, instead of a turbulent one aswould-be the case were the two pipes located on the same side of thetank.

- If an obstructionlodges in or against the end of the suction pipe,water will cease flowing into the tank through the pipe 4 undertheinfluence of the vacuum created in the upper portion of the tank 3.The pump vacuum, however, is unchanged, and since it is greater, to someextent than the vacuum in the tank 3, water will continue to flow fromthe tank through the pipe 50,

' thus lowering the water level perceptibly in the tank. In order toapprise the operator that water has ceased'to flow into the tank throughthe pipe 4, owing to some stoppage in the suction pipe, a gauge glass 3|is provided. It will be seen that if no steps are taken to free thesuction pipe, although no water is flowing into the tank 3, water willbe pumped out of the tank by the pump 20 until the vacuum in the upperpart of the tank approaches that of the vacuum which the pump 20 cancreate. Naturally the surface of the water 'will have dropped to a pointnear the bottom of the tank when such a vacuum is reached, and the dropwill appear in the gauge glass indicating to the operator that the pipe40 is obstructed. If the pipe is not cleared before the tank vacuumapproaches the pump vacuum in value, water will cease to flow throughthe pipe 5, and the pump will lose its prime.,-

If the end of the suction pipe 40 is projected only a small distancedown into the stream bed, it may easily be raised above the bed. If thestoppage is caused by a stone engaged over the end of the suction pipe.this may be released by closing the valve 4| for an instant, thusmomentarily cutting off the vacuum which enables the stone to be heldagainst the end of the suction pipe. more and the dredging operationcontinued without interruption, for ordinarily this manipulation can becompleted before the surface of the water in the tank 3 has beenlowered-to the critical point'a-twhich water ceases to be pumped out.

During the time the pipe 40 is being raised and the valve 4|, is beingshut and opened again, the water level in the tank 3 will have droppedinthe manner described, but since water has been continuously flowingthrough the pump 20 from the tank 50 the prime of the pump will not havebeen destroyed, nor will its operating volume ordinarily have decreasedmaterially. The vacuum in the The valve 4| may then be opened once thesuction pipe 40 is opened again, water willflow into'the tank 3 somewhatfaster than it flows out; and will continue to do so until anequilibrium has again been. reached where the level of the water in thetank 3 will be the same as it was originally,- namely, at about thecenter line of the pipe 5. Without the vacuum tank the pump would loseits prime almost immediately, and there would be nothing to warn theoperator that the suction pipe was blocked.

If the suction pipe 43 has been projected a considerable distance downinto the, ground, or it the obstruction is one which has lodged withinthe suction pipe, and is not merely a rock held against the end thereof,then it is desirable to force out the obstruction by positiveactionwithout raising the suction pipe. To accomplish this operation avalve 5| in the pipe 5 is closed and the pump 20 will lose its prime.The valve I will then be opened, and the pump 1| will pump stratum. Anypipe furnishing water under pres-- sure to the pipe 4, would, of course,drive out the obstruction. When the pipe has thus been cleared, thevalve will be opened and the valve 4| will be closed. Water will thus beforced down through the pipe '5 and through the pump 20 to prime thesame, to clear out any air pockets in the pipes 50 and 5, and to startthe pump 20 pumping at full capacity. Since the air in the top of thetank 3 has not been let out the pump will immediately operate at fullcapacity, drawing water from the tank 3, which for the moment is beingsupplied only by the pipe I. The water level will begin to drop to theoperating level at the center line of pipe 5. The valve 4| will now bereopened to resume the pumping operation, and the valve will be closed.

Thus although a positive force has been applied ,to the suction pipe 40by water flowing counter to the direction in which it normally flows,the pumping operation is interrupted for only a brief interval. When itis restarted the operation is at the full capacity of the pump, althoughthe pump has had to be reprimed. This operation is accomplished bypositively forcing water through the pipes 50 and 5 by water flowing inthrough the pipe 1, instead of allowing the vacuum and the operatingvolume of the pump to be built up gradually by the pump's own effort, asit would be necessary to do in the absence of the tank 3.

Whenthe valve Ill has been closed the water surface in the tank 3 maystill be higher than its normal level. Although the flow through thepipe 5 is normal in volume, the flow through the pipe 4 will be somewhatbelow normal until the water level in the tank has again dropped to itsequilibrium position, substantially at the center line of the pipe 5.

By the arrangement described it will be seen that a substantiallycontinuous pum ing operation is obtained, although momentarilyinterrupted at frequent intervals to clear the suction pipe. Without thevacuum tank 3 and with the pipe 5 connected directly to the suction pipe40 it will be seen that considerable delay must be entailed each timethe suction pipe 40 becomes blocked. The increased efliciency of oursystem will therefore be apparent.

What we claim as our invention is:

1. In a. pumping system of the type described, a suction pipe, anevacuating pump connected to saidsuction pipe, a pressure pipe adaptedfor communication with said suction pipe, and control means whereby to.interconnect for communication said suction pipe and said pressure pipeand to interrupt communication between said suction pipe and saidevacuating pump.

' 2. In a pumping system of the type described, a suction pipe, a pumpintake pipe, a pressure pipe, means interconnecting said three pipes, apump having its intake connected to, said intake pipe, and control meansoperable to close said suction pipe and to establish communicationbetween said pressure pipe and said pump intake pipe to forcibly primesaid pump, and there-.- after operable to establish communicationbetween said suction pipe and said pump intake pipe and to interruptcommunication between said pressure pipe and said pump intake pipe.

3. In a pumping system of the type described, a suction pipe, a pumpintake pipe, a pressure pipe, means interconnecting said, three pipes, apump having its intake connected to said intake pipe, and control meansoperable to close said pump intake pipe and to establish communicationbetween said pressure pipe and said suction pipe to force water outwardthrough the latter, or alternatively to close said pressure pipe and toestablish communication between said suction pipe and said pump intakepipe to draw water inward therethrough.

4. In a pumping system of the type described, a vacuum tank, a suctionpipe connected to said tank and discharging thereinto, an outflow pipeconnected to said tank and extending downward therein, a pump connectedto said outflow pipe, and a pressure pipe connected to said tank forpositively filling said tank with water.

5. In a pumping system of the type described, a vacuum tank, a suctionpipe and a pump intake pipe both connected to said tank, a pressure pipeconnected to the top of said vacuum tank, and valves, one in each ofsaid pipes, operable to establish communication between any two of saidpipes while the third pipe is closed, or alternativeiy operable toestablish communication between all three pipes, through said vacuumtank.,

6. In a pumping system of the ,type described, a vacuum tank, a suctionpipe connected thereto, a pump, a pipe interconnecting the pump intakeand the vacuum tank, a second pump, a pipe connecting the outlet of saidsecond pump to the top of said vacuum tank, and valves, one in each ofsaid pipes, operable to establish communicationthrough said vacuum tankbetween said sec- 0nd pumps outlet and said suction pipe to force out anobstruction in the latter, or operable to establish communicationthrough said tank between said second pumps outlet and said first pumpsintake to forcibly prime said first pump, or operable to establishcommunication through said tank between said suction pipe and said tankwith water, and means for admitting air to the upper end of said tank.

8. In a pumping system of the type described, a vacuum tank, a suctionpipe connected to said tank near the upper end thereof and dischargingthereinto, an imperforate outflow pipe terminating in a freely open endwithin and, near the bottom of said tank, extending upward in said tankto a point above the connection of said suction pipe with the tank, andthence outward through the wall of said tank, a pump having its inletconnected to said outflow pipe, a filling pipe connected to the upperend of said tank, and apet vacuum space in the top of the tank byoperating the pump to draw the water level down in the tank, and toinduce a flow of water and solid matter into the tank through thesuction pipe.

10. The method of pumping a mixture of water and solid matter with apump connected through a tank to a suction pipe, which comprises completely filling the tank with water, sealing the tank from ingress ofair, starting operation of the pump to draw water through the suctionpipe, tank filled with water, and pump, during such operatic-n admittinga small amount of air to the tank, to enable the pump to draw down thewater level therein to an equilibrium point, thereby inducing a flow ofwater and solid matter into the tank through the suction pipe, and outof the tank into the pump, and again sealing the tank from ingress oregress of air.

11. The method of operating a pump for the elevation of gravel, values,and the like, the intake pipe of which pump is liable to blocking by anobject held over the end thereof, which comprises providing a waterreservoir in the intake pipe between the open end thereof and thesuction pump, drawing water from the reservoir with and .through thepump to preserve its prime as soon as the intake pipe is blocked,raising the open end of the intake pipe above the surface of the bed butkeeping it beneath the surface of the water, closing the intake pipemomentarily to destroy thesuction therein and to release the obstructingobject while still drawing water from the reservoir with the pump topreserve its prime. and thereafter opening the intake pipe to draw watertherethroug'h in resumption of the normal pumping operation.

12. The method of operating a pump the intake -whereof is liable toblocking by an obstruction,

which comprises severing the communication of such intake with thesuction pump, forcing water in a reverse direction through the intakepipe to drive out the obstruction, forcing water in pumping directionthrough the pump to reprime it and force it into operation atsubstantially full capacity, and restoring communication between theintake pipe and the pump.

WILL S. TAYLOR. WILSON T. PRICE.

